If you work with sensitive information, you undoubtedly need ways to keep that information away from unauthorized eyes. File drawers and office doors can be locked - that's an obvious solution. But you also need to keep the information on your computer screen private while you work.

Privacy filters are not new, but they are necessary for many of you. When you're selecting one, be sure that you don't confuse privacy filters with anti-glare filters - they are not the same thing. Some anti-glare filters do also offer privacy protection, but many are just plain anti-glare.

There are several different manufacturers of privacy filters. Today I would like to showcase Fellowes brand. (2015 will be Fellowes' 98th year in business - Happy Anniversary!). They have a line of filters called PrivaScreen™ Blackout Privacy Filters.

These filters completely black out the image on the screen when viewed from the side, but it's crystal clear to anyone viewing it straight on, which hopefully, is just you. The filter also protects the screen from scratches and fingerprints. Here's a short video demonstration:

There is a wide selection of sizes available in the Fellowes line. In standard sizes, they offer ranges of 14.1" to 20.1" and in widescreen, the choices run from 13.3" to 24". Some are formatted for LCD displays only, but there is a larger selection that works on both LCD and notebook screens. See the entire line here.

The most common question I get in regard to monitor filters is "Can you help me figure out what size to buy?" That question usually comes from someone who has already purchased one and it doesn't fit their screen and they don't know what they did wrong. It's the single most common reason that filters are returned to us. To find the proper size, you need to remember this fact - when the description says "Fits 19" monitors," that doesn't mean the width of the monitor screen. The dimension listed refers to the diagonal measurement of the viewable area of the screen (from lower corner to opposite upper corner). The viewable area is just the screen itself - don't include the monitor frame when you're measuring it.

The other consideration in choosing the correct size is to know the aspect ratio of your monitor. A 19" monitor with a 16:9 ratio will have a smaller display area than a 19" monitor with a 4:3 ratio. Most newer monitors and laptops are 16:9, but some 16:10 and 4:3 still exist. If your monitor/laptop doesn't have the screen ratio printed on it, you can determine it by doing a simple calculation using the resolution, but it would probably be faster and easier to just ask your IT people.

Lastly, and very importantly, if you don't remember anything else that I've said here, remember this - even if you have a privacy filter on your computer, your boss still has ways to find out if you're playing Candy Crush on company time!